Shower Waterproofing

I'm very far into a tile job and just now flood testing my pan. Don't worry I would never do it in this order again....

First flood test failed massively. Leaks in the corners. Second flood test was much better, but I still had a leak on the curb.

Third test has resulted in some nail holes in my decking dripping water. When I flood test I have a good 3-4 inches of water in the pan all day.

I can't find the leak and I already basically waterproofed it twice as you can tell from the picture. I'm at my wits end and need help.

Questions I have right now:

1. How can I find this leak?

2. Do I have to find this leak?

3. Would it be crazy to just proceed?

Thanks in advance for your thoughts!

-Jackson W.